JPH0745175B2 - Method and device for expanding diameter of thermoplastic resin tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method and an apparatus for expanding the diameter of a thermoplastic resin tube.

Specifically, a diameter expanding method and apparatus for heating and softening the end of the thermoplastic resin tube and inserting a diameter expanding jig in order to perform the diameter expanding processing of the end of the tube made of a thermoplastic resin such as synthetic resin into a trumpet shape. Regarding

[Conventional technology]

Conventionally, the method of expanding the diameter of a thermoplastic resin tube utilizes the property that the thermoplastic resin tube is softened by heating, and a jig of a heating element having a predetermined expanded diameter is inserted into the end of the tube to expand the diameter. The method was used.

For example, the method described in JP-A-61-241129,
As shown in FIG. 15, after the diameter-expanding jig 102 such as a soldering iron having a diameter-expansion forming part 104 having a predetermined diameter-expansion shape (conical shape) is heated at the end 103 of the thermoplastic resin tube 101, this is expanded. The end 1
By forcibly inserting it into 03, the resin tube 10
A trumpet-shaped flange portion (diameter expansion portion) 105 is formed on the end portion 103 of 1.

[Problems to be Solved by the Invention]

However, in the case of the prior art, the temperature of the diameter expansion jig 102 is low, or the heating time is short, the resin tube is not sufficiently softened due to insufficient heating, and the predetermined diameter expansion dimension cannot be obtained. However, there is a drawback in that the resin tube 101 buckles when trying to insert the diameter-expanding jig 102 forcibly. Therefore, it is difficult to automate the diameter-expansion forming process, and the productivity is poor because it depends mainly on the skill of manual work.

Further, after the end portion 103 of the resin tube 101 is expanded, the end portion 1 of the resin tube 101 is stabilized in order to stabilize the expanded shape.
Cooling from the outside with the expansion jig 102 inserted in 03,
Alternatively, it is necessary to turn off the heating power source of the diameter expanding jig 102 to cool and solidify. At this time, the cooled resin adheres to the cooled diameter-expanding jig 102, which makes it difficult to remove the resin, resulting in defective products.

Therefore, the present invention was developed in view of the drawbacks of the above-mentioned conventional technology, does not require the skill of an operator, can obtain a stable diameter-expanded shape, and can be applied to the diameter-expansion jig of the resin tube. It is an object of the present invention to provide a method and an apparatus for expanding the diameter of a thermoplastic resin tube, which has a good productivity and can prevent the occurrence of defective products due to sticking.

[Means for Solving the Problems]

The present invention is a method of heating a molding portion of an end portion of a thermoplastic resin tube, and then performing a diameter-expanding molding by inserting a diameter-expanding jig into the molding portion of the tube. While facing a diameter-expanding jig having a blade-shaped taper portion, the tube molding portion and the diameter-expanding jig are heated by a predetermined heating temperature distribution and heating time,
The end portion of the thermoplastic resin tube is softened by heating, and,
The diameter-expanding jig is heated to a temperature higher than that of the molding portion of the thermoplastic resin tube, and the thermoplastic resin tube is moved while rotating and moving at least one of the end of the thermoplastic resin tube and the diameter-expanding jig in the molding direction. This is a method for expanding the diameter of a thermoplastic resin tube, which comprises subjecting an end portion of the resin tube to expansion molding in a trumpet shape and then cooling and solidifying.

Further, a wing piece shape having a taper portion is formed so that the holding portion projecting and holding the molding portion of the end portion of the thermoplastic resin tube and the molding portion of the resin tube held by the holding portion are radially expanded. A diameter-expanding jig having a diameter-expanding portion, a jig holding portion that holds the diameter-expanding jig so as to face the resin tube molding portion, a resin tube molding portion and the diameter-expanding jig are heated. In addition, a heating unit that heats the diameter-expanding jig to a temperature higher than the molding site, a rotation driving unit that rotates at least one of the resin tube or the diameter-expanding jig, and the resin tube or the diameter-expanding jig are moved. A movement driving means for inserting the expanded diameter portion into the molding portion of the resin tube, a rotation by the rotation driving means and a movement amount by the movement driving means are controlled, and the molding portion and the expansion jig are made to face each other. After heating for a predetermined time In a device for expanding the diameter of a thermoplastic resin tube, which comprises a control unit for controlling the molding part to expand and shape the trumpet shape while locating the winglet-shaped expanded part in the shaped part. is there.

[Action]

The method and apparatus for expanding the diameter of a thermoplastic resin tube of the present invention include heating the resin tube, heating a diameter expansion jig to a temperature higher than that of the resin tube, and expanding the resin tube and the diameter expansion treatment during expansion molding. By rotating at least one of the tools and moving them in the molding direction, stable diameter expansion molding can be performed, and it is possible to prevent the resin tube from sticking to the diameter expansion jig.

〔Example〕

Hereinafter, embodiments of a method and an apparatus for expanding the diameter of a thermoplastic resin tube of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 show a first embodiment of an apparatus used in the method for expanding the diameter of a thermoplastic resin tube of the present invention. FIG. 1 is a plan view, FIG. 2 is a side view, FIG. 3 is a side view of the diameter expanding jig, and FIG.
The figure shows a half-sectioned view of the diametrical expansion forming part, Fig. 5 (a), (b),
(C) is an explanatory view showing a diameter-expansion forming method, FIG. 6 is an explanatory view showing a heating state of a work and a diameter-expansion jig, FIG. 7 shows a chuck of the work, and FIG. 7 (a) shows a collet. Front view, No. 7
FIG. 8B is a sectional view of the wig, FIG. 8C is a front view of the chuck, FIG. 8 is an explanatory view showing the relationship between the heating temperature of the workpiece and the diameter-expanding jig, and the amount of movement in the molding direction. (A), (b)
Is a half cross-sectional view showing the diameter-expansion forming part, FIGS. 10 (a), (b)
Is a cross-sectional view showing a state where the workpiece is expanded and expanded, FIG. 11 (a),
(B) is a perspective view of a diameter-expanding jig, and FIG. 12 is an explanatory view showing a diameter-expansion forming state of a work.

In FIGS. 1 and 2, reference numeral 1 denotes a rectangular base, on which a holding portion 2 of a molding material (hereinafter referred to as a work) is placed on one side in the longitudinal direction. There is. A long work piece 3 (for example,
A rotatable spindle (not shown) including a chuck 4 for inserting and holding a Teflon tube or the like is provided. The chuck 4 is configured to be tightened in a collet chuck type as shown in FIG.

That is, it is composed of a collet 30 having a conical portion 31 and a slot 32 shown in FIG. 7 (a), and a wig 34 screwed to the screw portion 33 of the collet 30. After the work is mounted on the collet 30, the wig 34 is attached. Is configured to be rotatably held via a spindle by screwing and tightening on the collet 30.

A pulley 10a is fixed to the spindle of the chuck 4 and a drive pulley 10c is fixed to a drive shaft of a motor 9 arranged on the upper side of the base 1, and both pulleys 10a and 10c are connected by a belt 10b. Thus, the work held on the chuck 4 can be rotated.

On the upper side of the base 1, an electric drive type slide unit 6 is provided on the front side (right side in FIG. 1) of the work holding section 2, and the slide unit 6 is positioned by numerical control. A jig holding section 5 capable of performing the above is movably mounted along the guide rail 6a. On the upper part of the jig holding part 5, a diameter expanding jig 17 is provided on the same axis as the work 3.
A diameter-expanding jig insertion hole 7 for fitting and fixing is attached and a fixing screw 8 for fixing the fitted diameter-expanding jig 17 is provided.

As shown in FIG. 3, the diameter-expanding jig 17 includes a guide portion 19 having an outer diameter corresponding to the inner diameter of the molding portion of the workpiece 3 provided at the tip of the jig body 17a before the diameter is enlarged, and the jig body 17a. It is composed of a winglet-shaped expanded portion 20 having a taper portion at a predetermined angle with respect to the axis and a mounting portion 22 to be mounted in the jig insertion hole 7. Further, the slope of the diameter-enlarging taper portion of the diameter-enlarging portion 20 is chamfered or R-shaped so as not to damage the inner surface of the work 3 when the diameter is enlarged. Furthermore, the attachment part
22 is provided with a stopper 21 that keeps the amount of protrusion of the diameter-expanding jig 17 at the time of attachment to the jig insertion hole 7.
In addition, the above-described diameter-expanding jig 17 has an insertion portion 19 having a different outer diameter.
And a plurality of diameter-expanding jigs 17 having the diameter-expanding portion 20 are prepared and exchanged with the diameter-expanding jigs 17 corresponding to the inner diameter of the workpiece 3 to be subjected to the diameter-expansion forming and the diameter expansion. It is constructed so that it can be used for diameter expansion molding.

Further, the work 3 is provided above the base 1 (center in FIG. 1) between the work holding part 2 and the jig holding part 5.
Right angle to the axis of (Y direction, specifically the arrow direction in Fig. 1)
The heating unit 13 is mounted on the moving member 13a that moves to the inside, the guide unit 15 of the moving member 13a is laid, and the heating unit 13 is installed.
Is slidably engaged with the dovetail 15b of the moving member 13a corresponding to the dovetail of the guide portion 15 and is above the moving member 13a moving along the guide portion 15 via the holding piece 13b and the heating element 12b.
A cylinder mounted on the upper side of the base 1
By connecting 14 rods 14a to the moving member 13a, the air cylinder 14 is operated and the heating unit 13 is movable in the Y direction. Then, as shown in FIG.
Is the work 3 held on the bridge between the chuck 4 and the diameter expansion jig 17.
Is provided so that the heating temperature is distributed in the axial direction of the work 3 from the vicinity of the forming portion of the workpiece 3 to the vicinity of the expanded portion 20 of the expanding jig 17, and the tip portion of the forming portion of the workpiece 3 is farther than the base end side. The expanded diameter portion 20 of the expanded diameter jig 17 is tilted by the holding piece 13b so as to be heated to a higher temperature than the tip end portion.

Further, on the upper side of the base 1 at the end of the passage where the heating unit 13 moves in the Y direction (the direction of the arrow in FIG. 1), position sensors 16a and 16b for controlling the positioning of the heating unit 13 are provided at the work heating position and the retracted position, respectively. is set up.

Further, at the position of the side portion (right side in FIG. 1) of the base 1, the rotational drive / rotation speed of the holding portion 2 and the motor 9 which is the driving portion, and the movement of the slide unit 6 which is the driving portion of the jig holding portion 5 are moved. A control unit 23 is provided for controlling the speed, the movement of the air cylinder 14 which is the drive unit of the heating unit 13, the heating time / cooling time, the operation timing between the respective units 2, 5, 13, and the like.

The diameter-expansion forming process of the work 3 using the apparatus having the above-described configuration is performed by the diameter-expansion jig 17 having the diameter-expansion portion 20 having a predetermined diameter-expansion shape.
When the work piece 3 is attached to the chuck 4 by the fixing screw 8 when the mounting portion 22 of the is fitted into the diameter-expanding jig insertion hole 7 of the jig holding portion 5 and the stopper 21 hits the opening end of the insertion hole 7. Then, the workpiece 3 is clamped and fixed on the same axis as the workpiece 3 and the expanded diameter portion 20 is parallel to the base 1. Next, the jig holder 5
After moving to the work attaching position, the work 3 is inserted into the work holding portion 2 and the wig 34 is penetrated through the chuck 4 which has been loosened in advance. Then, when the open end of the forming portion of the work 3 hits the base end portion of the expanded diameter portion 20 provided in the expansion jig 17, the wig 34 of the chuck 4 is clamped to the collet 30 and the workpiece 3 is held in the holding portion 2. Fix it.

Then, the control unit sets the processing conditions (heating time, heating temperature, expansion jig insertion speed, expansion jig initial position, expansion jig insertion amount) for obtaining a molded product of a predetermined expansion shape. Operate the start button of 23 to operate the sequence and start the molding process.

First, the motor 9 is driven to rotate the work 3, and the heating body 12
When the heating temperature reaches a certain level, the heating unit 13 is moved to a heating position directly below the work 3 and the work 3 is rotated while being heated with a predetermined temperature distribution for a predetermined time (fifth time). (See Figure a). At this time, due to the heating unit 13, the diameter-expanding jig 17 is at a higher temperature than the forming portion of the work 3.

After heating for a predetermined time, the jig holding part 5 having the diameter expanding jig 17 mounted thereon is moved toward the work 3 at a predetermined speed by a predetermined amount to expand the diameter (see FIGS. 5B and 5C).

As shown in FIG. 5B, the opening end of the forming portion of the work 3 is initially rotated and is offset toward the enlarged diameter portion 19. After that, when heating is performed for a predetermined time while rotating at a constant position (diameter expansion position), the open end of the molding portion of the work 3 which is gradually softened as shown in FIG. Then heated
The work 3 is solidified by stopping the heat generation of 12 and air cooling. After air cooling for a required time, the heating unit 13 is returned to the initial position, and the jig holding unit 5 is also returned to the initial position to stop the rotation of the motor 8.

Table 1 below shows an example of the molding processing conditions according to the present embodiment.

A heating temperature distribution by the heating body 12 under the above various conditions is shown in the form of a graph, and the mounting position of the work 3 and the insertion amount of the diameter-expanding jig with respect to the heating temperature distribution of the graph are shown in FIG. As shown in FIG. 8, the temperature of the diameter-expanding jig 17 is set to be higher than the temperature of the opening end of the forming portion of the work 3. This is because if the temperature of the expanding jig is low,
This is because the opening end of the forming portion of the work 3 is cooled when the diameter expanding jig is inserted, and softening sufficient to expand the diameter cannot be obtained.

According to the present embodiment, the work 3 is rotated while being held straight, and after heating, a diameter expansion jig is inserted and air cooling is performed to obtain a trumpet-shaped diameter expansion part that is axially symmetrical to the work 3. To be

Also, by changing the heating element 12, the diameter-expanding jig 17, the heating temperature, the heating time, the jig insertion amount, and the jig insertion speed, it is possible to handle trumpet-shaped molding with various angles and diameters. It is possible to improve efficiency in high-mix low-volume production.

Further, since the work 3 is not welded to the diameter expanding jig 17, there is an advantage that the molded product can be taken out reliably and easily.

The present invention is not limited to the embodiment, and the work holding unit 2 is configured to be movable, the jig holding unit 5 is fixed to the base 1, and the work 3 is heated for a predetermined time and then rotated. However, the workpiece holder 2 is moved by a predetermined amount to expand the diameter. Further, the heating body 12 is formed in a substantially ring shape, and a slit is provided in the axial direction of the work 3 so as not to interfere with the work 3 when the heating unit 13 moves. Further, the diameter expanding jig 17 is rotated without rotating the work 3,
The diameter expanding jig 17 is inserted into the non-rotating work 3 while rotating to expand the diameter. Also, the work 3 and the diameter expansion jig
It is possible to adopt a configuration in which the diameter-expanding jig 17 is inserted into the work 3 while rotating 17 relative to each other, and the same effect as that of the embodiment can be obtained.

Further, the shape of the diameter expanding jig 17 is not limited to the shape shown in FIG. 3, and a plurality of diameter expanding portions 20 can be provided as shown in FIGS. Furthermore, as shown in Fig. 12, the expanded diameter part
20 can be stepped or flanged. However, the increase in the contact area between the inner surface of the work 3 and the expanded diameter portion 20 means that
This increases the friction between the inner surface of the work 3 and the expanded diameter portion 20,
Problems such as twisting of the work 3 may occur during the expansion molding. Therefore, the inner surface of the work 3 and the enlarged diameter portion are not twisted.
It is necessary to consider the contact area with 20.

(Second Embodiment) FIGS. 13 and 14 show a second embodiment of the thermoplastic resin tube diameter expanding method and apparatus according to the present invention, and FIG. 13 is an explanatory view of a variable diameter expanding jig portion, FIGS. 14a and 14b are explanatory views at the time of diameter expansion molding.

The apparatus used for the method of expanding the diameter of the thermoplastic resin tube shown in the embodiment is the same as the expanding jig 17 of the first embodiment except that the expanding jig 17 is replaced by a variable expanding jig part 24 and the upper part of the jig holding part 5 is changed. It is different in that it is provided with a cylinder 29, and the other configurations are the same configurations. The other configurations are denoted by the same reference numerals and the description thereof is omitted.

The variable diameter expansion jig portion 24 includes a shaft 25, a wing portion 27 rotatably fixed by a pin 26 between a slit provided in the axial direction of the shaft 25, and a cam groove 28 in the wing portion 27. Is provided.

The cylinder 29 is provided above the jig holding portion 5, the cylinder rod 29a of the cylinder 29 is connected to the cam groove 28 of the variable diameter expanding jig portion 24, and the wing portion 27 is opened and closed by advancing and retracting the cylinder rod 29a. Is configured.

The diameter expansion method using the apparatus having the above-described configuration is performed by inserting the diameter expansion forming part of the work 3 into the tip of the shaft 25 of the variable diameter expansion jig part 24, setting the work 3 at a predetermined heating position, and chucking. Four
Tighten and fix with. Then, the work 3 and the variable diameter expansion jig portion 24 are heated while rotating the work 3 as in the first embodiment. After heating for a predetermined time, the cylinder rod 29a of the cylinder 29 is gradually projected to push out the wing 27.
The diameter-expanded forming portion of the work 3 that has been softened by heating is gradually expanded in the shape of the wing portion 27. The cylinder 29 is stopped when the wing portion 27 spreads to a predetermined angle, and the diameter-expansion forming is performed while heating the diameter-expansion forming part of the work 3 until the diameter-expansion forming part expands axially symmetrically. After the expansion molding is completed, the heating by the heating body 12 is stopped and air cooling is performed for a predetermined time. After the expanding portion of the workpiece 3 is solidified by air cooling, the cylinder rod 29a of the cylinder 29 is retracted to move the wing portion 2
Close 7 to the initial position. Then, the chuck 4 is loosened and the work 3 is removed.

According to the present embodiment, since the diameter expansion angle can be changed according to the amount of protrusion of the cylinder rod 29a of the cylinder 29, it is not necessary to prepare a plurality of diameter expansion jigs when expanding the diameter of different shapes. It can be used for a variety of small-scale production.

〔The invention's effect〕

As described above, according to the method and apparatus for expanding the diameter of the thermoplastic resin tube of the present invention, remarkable effects such as stable production of various kinds of trumpet-shaped expansion-expanding molded parts with good quality can be obtained.

[Brief description of drawings]

1 to 12 show a first embodiment of an apparatus used for the method for expanding the diameter of a thermoplastic resin tube of the present invention. FIG. 1 is a plan view, FIG. 2 is a side view, and FIG. Side view of diameter jig, 4th
The figure shows a half-sectioned view of the diametrical expansion forming part,
(C) is an explanatory view showing a diameter-expansion forming method, FIG. 6 is an explanatory view showing a heating state of a work and a diameter-expansion jig, FIG. 7 is a chuck of the work, and FIG. 7 (a) is a front view. 7 (b) is a cross-sectional view of the wig, FIG. 7 (c) is a front view of the chuck, and FIG. 8 shows the relationship between the heating temperature of the workpiece and the diameter-expanding jig and the movement amount in the molding direction. Explanatory drawing, FIG. 9 (a), (b) is a semi-divided sectional view showing the expanded diameter forming state, FIG. 10 (a), (b) is a sectional view showing the expanded diameter forming state of the work, FIG. 11 ( a),
(B) is a perspective view of the diameter expansion jig, FIG. 12 is an explanatory view showing the diameter expansion forming state of the work, FIGS. 13 and 14 show the second embodiment, and FIG. 13 is a variable diameter expansion. An explanatory view of the jig, FIGS. 14 (a) and 14 (b) are explanatory views at the time of diameter expansion molding, and FIG. 15 is a partially sectional side view showing a conventional example. 1 ... Base 2 ... Holding part 3 ... Thermoplastic resin tube 5 ... Jig holding part 6 ... Slide unit 9 ... Motor 13 ... Heating part 14 ... Air cylinder 17 ... Expanding jig 23 …… Control unit 24 …… Variable diameter expansion jig

Claims (2)

[Claims] 1. A method for expanding a thermoplastic resin tube by heating a molded part at the end of the thermoplastic resin tube and then inserting a diameter-expanding jig into the molded part of the tube. And a diameter-expanding jig having a winglet-shaped taper portion are made to face each other, and the molded portion of the tube and the diameter-expanding jig are heated by a predetermined heating temperature distribution and heating time, and the end portion of the thermoplastic resin tube By heating and softening, and heating the diameter-expanding jig to a temperature higher than the molding site of the thermoplastic resin tube, and rotating at least one of the end of the thermoplastic resin tube and the diameter-expanding jig and the molding direction. A method for expanding the diameter of a thermoplastic resin tube, characterized in that the end part of the thermoplastic resin tube is subjected to expansion molding in a trumpet shape while being moved to, and then cooled and solidified. 2. A blade having a holding portion for projecting and holding a molding portion of an end portion of a thermoplastic resin tube, and a blade having a taper portion for expanding and molding the molding portion of the resin tube held by the holding portion. A diameter-expanding jig having a piece-shaped diameter-expanding portion, a jig holding portion for holding the diameter-expanding jig in opposition to a molding portion of the resin tube, a molding portion of the resin tube, and the diameter-expanding treatment. A heating unit that heats the tool and heats the diameter-expanding jig to a temperature higher than the molding site; a rotation driving unit that rotates at least one of the resin tube and the diameter-expanding jig; and the resin tube or the diameter-expanding jig. A moving drive means for moving and inserting the expanded diameter portion into the molding portion of the resin tube, a rotation by the rotation driving means and a movement amount by the movement driving means are controlled, and the molding portion and the expansion jig are Let them face each other and heat for a predetermined time A device for expanding the diameter of a thermoplastic resin tube, characterized in that it comprises a control unit for controlling to expand and form the forming part into a trumpet shape while locating the winglet-like expanding part inside the forming part. .